Olefin trimerisation using a catalyst comprising a source of chromium, molybdenum or tungsten and a ligand containing at least one phosphorous, arsenic or antimony atom bound to at least one (hetero) hydrocarbyl group

ABSTRACT

A process for the trimerisation of olefins is disclosed, comprising contacting a monomeric olefin or mixture of olefins under trimerisation conditions with a catalyst which comprises (a) a source of chromium, molybdenum or tungsten (b) a ligand containing at least one phosphorus, arsenic or antimony atom bound to at least one hydrocarbyl or heterohydrocarbyl group having a polar substituent, but excluding the case where all such polar substituents are phosphane, arsane or stibana groups; and optionally (c) an activator.

This invention relates to the trimerisation of olefins, such as thepreparation of 1-hexene by the trimerisation of ethylene.

U.S. Pat. No. 5,198,563 and related patents by Phillips describechromium-containing catalysts containing monodentate amide ligandsuseful for trimerising olefins.

U.S. Pat. No. 5,968,866 discloses an ethyleneoligomerisation/trimerisation process which uses a catalyst comprising achromium complex which contains a coordinating asymmetric tridentatephosphane, arsane or stibane ligand (referred to therein as phosphine,arsine or stibine, and representing a phosphorus, arsenic or antimonyatom attached to three hydrocarbyl groups) and an aluminoxane to producealpha-olefins which are enriched in 1-hexene. There is no suggestionthat it is possible to replace any of the phosphane, arsane or stibanegroups: indeed, it is impossible to predict what the effect of such areplacement would be.

We have now discovered further ligands which when used in conjunctionwith a source of a Group 3 to 10 transition metal are significantly moreactive as trimerisation catalysts than those currently known, and alsoshow other advantageous properties. The invention also encompasseswithin its scope novel catalysts comprising such ligands in conjunctionwith a source of chromium, molybdenum or tungsten.

Accordingly in a first aspect, the present invention provides a catalystfor the trimerisation of olefins, comprising

-   (a) a source of chromium, molybdenum or tungsten;-   (b) a ligand containing at least one phosphorus, arsenic or antimony    atom bound to at least one hydrocarbyl or heterohydrocarbyl group    having a polar substituent, but excluding the case where all such    polar substituents are phosphane, arsane or stibane groups; and    optionally-   (c) an activator.

In this specification the term “trimerisation” means catalytic reactionof a single olefinic monomer or a mixture of olefinic monomers to giveproducts enriched in those constituents derived from the reaction(s) ofthree olefinic monomers, as distinct from polymerisation oroligomerisation, which typically give olefinic product distributionsgoverned by either a geometric series equation or following a Poissonpattern of distribution. “Trimerisation” includes the case where all themonomer units in the trimerisation product are identical, where thetrimerization product is made from two different olefins (i.e. twoequivalents of one monomer react with one equivalent of a secondmonomer), and also where three different monomer units react to yieldthe product. A reaction involving more than one monomer is oftenreferred to as cotrimerisation.

It will be appreciated that the above catalyst may either be formedprior to use in a trimerisation reaction, or it may be formed in situ byadding the individual components thereof to the reaction mixture.

In a further aspect, the invention provides a process for thetrimerisation of olefins, comprising contacting a monomeric olefin ormixture of olefins under trimerisation conditions with a catalyst whichcomprises

-   (a) a source of a Group 3 to 10 transition metal;-   (b) a ligand containing at least one phosphorus, arsenic or antimony    atom bound to at least one hydrocarbyl or heterohydrocarbyl group    having a polar substituent, but excluding the case where all such    polar substituents are phosphane, arsane or stibane groups; and    optionally-   (c) an activator.

We have also found that the catalysts used in the above process havecertain novel features. For example, such catalysts when supported loseless of their activity compared with the equivalent unsupported catalystthan known catalysts. A further aspect of the invention therefore is asupported catalyst having a productivity per mole of catalyst of atleast 50%, preferably at least 70% of its productivity when unsupported,which catalyst preferably comprises

-   (a) a source of a Group 3 to 10 transition metal;-   (b) a ligand containing at least one phosphorus, arsenic or antimony    atom bound to at least one hydrocarbyl or heterohydrocarbyl group    having a polar substituent, but excluding the case where all such    polar substituents are phosphane, arsane or stibane groups; and    optionally-   (c) an activator.

Additionally, we have found that such catalysts have unusually highproductivity, and maintain that productivity particularly well.Accordingly one further aspect of the invention comprises a catalyst forthe trimerisation of olefins, which has a productivity of at least 30000g product per mmol catalyst per hour at a temperature of 110° C. or lessand an ethylene partial pressure of 21 bar or less. Another aspect ofthe invention is a catalyst for the trimerisation of olefins, whereinthe catalyst productivity decays at a rate of less than 10% per hour.

In one embodiment of the process of the invention, the catalyst utilisedin the present invention additionally comprises a further catalyst (d)suitable for the polymerisation, oligomerisation or other chemicaltransformations of olefins. In processes wherein such an additionalcatalyst is present, the trimerisation products are incorporated into ahigher polymer or other chemical product.

The catalysts used in the trimerisation process of the invention showexceptionally high productivity and selectivity to 1-hexene within theproduct fraction containing 6 carbon atoms. The high productivity of thecatalysts results in greater process efficiency and/or lower intrinsiclevels of catalyst residues. The high selectivity of the catalystsresults in a greater ease of product purification (resulting either inless costly product purification or purer products). These advantageswould be expected to apply both to processes wherein catalysts accordingto the invention comprise the sole catalytic component and also tointegrated processes, for example in the production of branchedpolyolefins, where more than one transition metal catalyst is employed.

As regards the source of Group 3 to 10 transition metal (a), this caninclude simple inorganic and organic salts, for example, halides,acetylacetonates, carboxylates, oxides, nitrates, sulfates and the like,as well as co-ordination and organometallic complexes, for example,chromium trichloride tetrahydrofuran complex,(benzene)tricarbonylchromium, chromium hexacarbonyl, molybdenumhexacarbonyl and the like. Preferably component (a) is a source ofchromium, molybdenum or tungsten; particularly preferred is chromium.

The ligand of component (b) preferably has the formula(R¹)(R²)X—Y—X(R³)(R⁴), wherein

-   -   X is phosphorus, arsenic or antimony;    -   Y is a linking group;    -   and R¹, R², R³ and R⁴ are each independently hydrocarbyl,        substituted hydrocarbyl, heterohydrocarbyl or substituted        heterohydrocarbyl groups, at least one of which has a polar        substituent which is not a phosphane, arsane or stibane group.

An alternative preferred structure for the ligand of component (b) isX(R¹)(R²)(R³) wherein X and R¹, R² and R³ are as defined above, with atleast one of R¹, R² and R³ having a polar substituent which is not aphosphane, arsane or stibane group.

X is preferably phosphorus. As regards R¹, R², R³ and R⁴, examples ofsuitable hydrocarbyl groups are methyl, ethyl, ethylenyl, propyl, butyl,cyclohexyl, benzyl, phenyl, tolyl, xylyl, mesityl, biphenyl, naphthyl,anthracenyl and the like. Examples of suitable heterohydrocarbyl groupsare methoxy, ethoxy, phenoxy (i.e. —OC₆H₅), tolyloxy (i.e. —OC₆H₄(CH₃)),xylyloxy, mesityloxy, dimethylamino, diethylamino, methylethylamino,thiomethyl, thiophenyl, trimethylsilyl, dimethylhydrazyl and the like.

Preferably those of R¹ to R⁴ having polar substituents are substitutedaryl groups with at least one polar substituent. Suitable substitutedaryl groups include substituted phenyl, substituted naphthyl andsubstituted anthracenyl groups. Substituted phenyl is preferred. Polarsubstituents include methoxy, ethoxy, isopropoxy, C₃-C₂₀ alkoxy,phenoxy, pentafluorophenoxy, trimethylsiloxy, dimethylamino,methylsulphanyl, tosyl, methoxymethyl, methylthiomethyl, 1,3-oxazolyl,methoxymethoxy, hydroxyl, amino, sulphate, nitro and the like. Othersuitable polar substituents include phosphanes, arsanes and stibanes asdescribed in U.S. Pat. No. 5,968,866 (but subject to the above-mentionedproviso that at least one of R¹ to R⁴ has a polar substituent which isnot one of these). Ortho-substituted phenyl groups are most preferred;the ortho substituent is preferably alkoxy, more preferably methoxy ormethoxymethoxy. The phenyl groups may additionally be substituted in themeta and para or other ortho positions by groups such as hydrocarbyl,heterohydrocarbyl, substituted hydrocarbyl, halide and the like; but itis preferred that they are unsubstituted in these other positions.

Preferably any of R¹ to R⁴ which do not have polar substituents areindependently optionally substituted phenyl groups; substituents may behydrocarbyl, heterohydrocarbyl, substituted hydrocarbyl, substitutedheterohydrocarbyl, halide and the like. However it is most preferredthat all of R¹ to R⁴ have polar substituents as defined above, which arenot phosphane, arsane or stibane groups. It is also most preferred thatR¹ to R⁴ are the same.

Y may be any bridging group, for example hydrocarbyl, substitutedhydrocarbyl, heterohydrocarbyl, substituted hydrocarbyl or substitutedheterohydrocarbyl bridging groups, or inorganic bridging groupsincluding single atom links such as —O—. Y may optionally contain anadditional potential donor site. Examples of Y include methylene,1,2-ethane, 1,2-phenylene, 1,3-propane, 1,2-catechol,1,2-dimethylhydrazine, —N(R⁵)— where R⁵ is hydrogen, hydrocarbyl, orsubstituted hydrocarbyl, and the like. Preferably Y is —N(R⁵)—;preferably R⁵ is hydrogen, C₁-C₆ alkyl or phenyl, more preferablymethyl.

Any of the groups R¹-R⁴ may independently be linked to one or more ofeach other or to the bridging group Y, to form a cyclic structuretogether with X or X and Y.

The ligands can be prepared using procedures known to one skilled in theart and disclosed in published literature. Examples of preferredcompounds are:

-   (2-methoxyphenyl)(phenyl)PN(Me)P(phenyl)₂-   (2-methoxyphenyl)₂PN(Me)P(phenyl)₂-   (2-methoxyphenyl)(phenyl)PN(Me)P(2-methoxyphenyl)(phenyl)-   (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂-   (2-ethoxyphenyl)₂PN(Me)P(2-ethoxyphenyl)₂-   (2-isopropoxyphenyl)₂PN(Me)P(2-isopropoxyphenyl)₂-   (2-hydroxyphenyl)₂PN(Me)P(2-hydroxyphenyl)₂-   (2-nitrophenyl)₂PN(Me)P(2-nitrophenyl)₂-   (2,3-dimethoxyphenyl)₂PN(Me)P(2,3dimethoxyphenyl)₂-   (2,4-dimethoxyphenyl)₂PN(Me)P(2,4-dimethoxyphenyl)₂-   (2,6-dimethoxyphenyl)₂PN(Me)P(2,6-dimethoxyphenyl)₂-   (2,4,6-trimethoxyphenyl)₂PN(Me)P(2,4,6-trimethoxyphenyl)₂-   (2-dimethoxyphenyl)(2-methylphenyl)PN(Me)P(2-methylphenyl)₂-   [2-(dimethylamino)phenyl]2PN(Me)P[2-(dimethylamino)phenyl]₂-   (2-methoxymethoxyphenyl)₂PN(Me)P(2-methoxymethoxyphenyl)₂-   (2-methoxyphenyl)₂PN(Ethyl)P(2-methoxyphenyl)₂-   (2-methoxyphenyl)₂PN(Phenyl)P(2-methoxyphenyl)₂-   (2-methoxyphenyl)₂PN(Me)N(Me)P(2-methoxyphenyl)₂-   (2-methoxyphenyl)₂PCH₂P(2-methoxyphenyl)₂-   (2-methoxyphenyl)₂PCH₂CH₂P(2-methoxyphenyl)₂-   tri(2-methoxymethoxyphenyl)phosphane i.e.-   tri(2-methoxyphenyl)phosphane.

Components (a) and (b) may be present in any ratio, preferably between10000:1 and 1:10000; more preferred is a ratio between 100:1 and 1:100,and especially preferred is a ratio of 10:1 to 1:10, particularly 3:1 to1:3. Generally the amounts of (a) and (b) are approximately equal, ie aratio of between 1.5:1 and 1:1.5.

The activator compound (c) may in principle of be any compound thatgenerates an active catalyst with components a) and b). Mixtures ofactivators may also be used. Suitable compounds include organoaluminiumcompounds, organoboron compounds and inorganic acids and salts, such astetrafluoroboric acid etherate, silver tetrafluoroborate, sodiumhexafluoroantimonate and the like. Suitable organoaluminium compoundsinclude compounds of the formula AlR₃, where each R is independentlyC₁-C₁₂ alkyl, oxygen or halide, and compounds such as LiAlH₄ and thelike. Examples include trimethylaluminium (TMA), triethylaluminium(TEA), tri-isobutylaluminium (TIBA), tri-n-octylaluminium,methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminiumchloride, diethylaluminium chloride, ethylaluminiumsesquichloride,methylaluminiumsesquichloride, and alumoxanes. Alumoxanes are well knownin the art as typically oligomeric compounds which can be prepared bythe controlled addition of water to an alkylaluminium compound, forexample trimethylaluminium. Such compounds can be linear, cyclic, cagesor mixtures thereof. Commercially available alumoxanes are generallybelieved to be mixtures of linear and cyclic compounds. The cyclicalumoxanes can be represented by the formula [R⁶AlO]_(s) and the linearalumoxanes by the formula R⁷(R⁸AlO)_(s) wherein s is a number from about2 to 50, and wherein R⁶, R⁷, and R⁸ represent hydrocarbyl groups,preferably C₁ to C₆ alkyl groups, for example methyl, ethyl or butylgroups. Alkylalumoxanes such as methylalumoxane (MAO) are preferred.

Mixtures of alkylalumoxanes and trialkylaluminium compounds areparticularly preferred, such as MAO with TMA or TIBA. In this context itshould be noted that the term “alkylalumoxane” as used in thisspecification includes alkylalumoxanes available commercially which maycontain a proportion, typically about 10 wt %, but optionally up to 50wt %, of the corresponding trialkylaluminium; for instance, commercialMAO usually contains approximately 10 wt % trimethylaluminium (TMA),whilst commercial MMAO contains both TMA and TIBA. Quantities ofalkylalumoxane quoted herein include such trialkylaluminium impurities,and accordingly quantities of trialkylaluminium compounds quoted hereinare considered to comprise compounds of the formula AlR₃ additional toany AlR₃ compound incorporated within the alkylalumoxane when present.

Examples of suitable organoboron compounds are boroxines, NaBH₄,trimethylboron, triethylboron,dimethylphenylammoniumtetra(phenyl)borate, trityltetra(phenyl)borate,triphenylboron, dimethylphenylammonium tetra(pentafluorophenyl)borate,sodium tetrakis[(bis-3,5-trifluoromethyl)phenyl]borate,H⁺(OEt₂)₂[(bis-3,5-trifluoromethyl)phenyl]borate,trityltetra(pentafluorophenyl)borate and tris(pentafluorophenyl) boron.

Activator compound (c) may also be or contain a compound that acts as areducing or oxidising agent, such as sodium or zinc metal and the like,or oxygen and the like.

In the preparation of the catalysts utilised in the present invention,the quantity of activating compound to be employed is easily determinedby simple testing, for example, by the preparation of small test sampleswhich can be used to trimerise small quantities of the monomer(s) andthus to determine the activity of the produced catalyst It is generallyfound that the quantity employed is sufficient to provide 0.1 to 20,000atoms, preferably 1 to 2000 atoms of aluminium or boron per atom ofchromium. In some cases, for particular combinations of component a) andb), an activating compound c) may not be required.

Components (a)-(c) of the catalyst system utilised in the presentinvention may be added together simultaneously or sequentially, in anyorder, and in the presence or absence of monomer in any suitablesolvent, so as to give an active catalyst. For example, components (a),(b) and (c) and monomer may be contacted together simultaneously, orcomponents (a), (b) and (c) may be added together simultaneously orsequentially in any order and then contacted with monomer, or componentsa) and b) may be added together to form an isolable metal-ligand complexand then added to component c) and contacted with monomer, or components(a), (b) and (c) may be added together to form an isolable metal-ligandcomplex and then contacted with monomer. Suitable solvents forcontacting the components of the catalyst or catalyst system include,but are not limited to, hydrocarbon solvents such as heptane, toluene,1-hexene and the like, and polar solvents such as diethyl ether,tetrahydrofuran, acetonitrile, dichloromethane, chloroform,chlorobenzene, methanol, acetone and the like.

The catalyst components (a), (b) and (c) utilised in the presentinvention can be unsupported or supported on a support material, forexample, silica, alumina, MgCl₂ or zirconia, or on a polymer, forexample polyethylene, polypropylene, polystyrene, or poly(aminostyrene).It is an advantage of the present invention that very littleproductivity (mass of product per mol of catalyst per hour) is lost whenthe catalyst is supported. If desired the catalysts can be formed insitu in the presence of the support material, or the support materialcan be pre-impregnated or premixed, simultaneously or sequentially, withone or more of the catalyst components. The quantity of support materialemployed can vary widely, for example from 100,000 to 1 grams per gramof metal present in the transition metal compound. In some cases, thesupport may material can also act as or as a component of the activatorcompound (c). Examples include supports containing alumoxane moietiesand/or hydrocarbyl boryl moieties (see, for example, Hlatky, G. G. Chem.Rev. 2000, 100, 1347.)

One embodiment of the present invention encompasses the use ofcomponents (a) (b) and optionally (c) in conjunction with one or moretypes of olefin polymerisation catalyst or catalyst system (d) totrimerise olefins and subsequently incorporate a portion of thetrimerisation product(s) into a higher polymer.

Component (d) may be one or more suitable polymerisation catalyst(s) orcatalyst system(s), examples of which include, but are not limited to,conventional Ziegler-Natta catalysts, metallocene catalysts,monocyclopentadienyl or “constrained geometry” catalysts, heat activatedsupported chromium oxide catalysts (eg. “Phillips”-type catalysts), latetransition metal polymerisation catalysts (eg. diimine, diphosphine andsalicylaldimine nickel/palladium catalysts, iron and cobaltpyridyldiimine catalysts and the like) and other so-called “single sitecatalysts” (SSC's).

Ziegler-Natta catalysts, in general, consist of two main components. Onecomponent is an alkyl or hydride of a Group I to III metal, mostcommonly Al(Et)₃ or Al(iBu)₃ or Al(Et)₂Cl but also encompassing Grignardreagents, n-butyllithium, or dialkylzinc compounds. The second componentis a salt of a Group IV to VIII transition metal, most commonly halidesof titanium or vanadium such as TiCl₄, TiCl₃, VCl₄, or VOCl₃. Thecatalyst components when mixed, usually in a hydrocarbon solvent, mayform a homogeneous or heterogeneous product. Such catalysts may beimpregnated on a support, if desired, by means known to those skilled inthe art and so used in any of the major processes known forco-ordination catalysis of polyolefins such as solution, slurry, andgas-phase. In addition to the two major components described above,amounts of other compounds (typically electron donors) maybe added tofurther modify the polymerization behaviour or activity of the catalyst.

Metallocene catalysts, in general, consist of transistion metalcomplexes, most commonly based on Group IV metals, ligated withcyclopentadienyl(Cp)-type groups. A wide range of structures of thistype of catalysts is known, including those with substituted, linkedand/or heteroatom-containing Cp groups, Cp groups fused to other ringsystems and the like. Additional activators, such as boranes oralumoxane, are often used and the catalysts may be supported, ifdesired.

Monocyclopentadienyl or “constrained geometry” catalysts, in general,consist of a transition metal complexes, most commonly based on Group IVmetals, ligated with one cyclopentadienyl(Cp)-type group, often linkedto additional donor group. A wide range of structures of this type ofcatalyst is known, including those with substituted, linked and/orheteroatom-containing Cp groups, Cp groups fused to other ring systemsand a range of linked and non-linked additional donor groups such asamides, amines and alkoxides. Additional activators, such as boranes oralumoxane, are often used and the catalysts may be supported, ifdesired.

A typical heat activated chromium oxide (Phillips) type catalyst employsa combination of a support material to which has first been added achromium-containing material wherein at least part of the chromium is inthe hexavalent state by heating in the presence of molecular oxygen. Thesupport is generally composed of about 80 to 100 wt. % silica, theremainder, if any, being selected from the group consisting ofrefractory metal oxides, such as aluminium, boria, magnesia, thoria,zirconia, titania and mixtures of two or more of these refractory metaloxides. Supports can also comprise alumina, aluminium phosphate, boronphosphate and mixtures thereof with each other or with silica. Thechromium compound is typically added to the support as a chromium (III)compound such as the acetate or acetylacetonate in order to avoid thetoxicity of chromium (VI). The raw catalyst is then calcined in air at atemperature between 250 and 1000° C. for a period of from a few secondsto several hours. This converts at least part of the chromium to thehexavalent state. Reduction of the Cr (VI) to its active form normallyoccurs in the polymerization reaction, but can be done at the end of thecalcination cycle with CO at about 350° C. Additional compounds, such asfluorine, aluminium and/or titanium may be added to the raw Phillipscatalyst to modify it.

Late transition metal and single site catalysts cover a wide range ofcatalyst structures based on metals across the transition series (see,for example, Britovsek, G. J. P et al. Angew. Chem. Int. Ed. Engl. 1999,38, 429. and Ittel, S. D. et al. Chem. Rev. 2000, 100, 1169.

Component (d) may also comprise one or more polymerisation catalysts orcatalyst systems together with one or more additional oligomerisationcatalysts or catalyst systems. Suitable oligomerisation catalystsinclude, but are not limited to, those that dimerise (for example,nickel phosphine dimerisation catalysts) or trimerise olefins orotherwise oligomerise olefins to, for example, a distribution of1-olefins governed by a geometric series equation (for example, iron andcobalt pyridyldiimine oligomerisation catalysts).

Component (d) may independently be supported or unsupported. Wherecomponents (a) and (b) and optionally (c) are supported, (d) may beco-supported sequentially in any order or simultaneously on the samesupport or may be on a separate support. For some combinations, thecomponents (a)-(c) may be part or all of component (d). For example, ifcomponent (d) is a heat activated chromium oxide catalyst then this maybe (a), a chromium source and if component (d) contains an alumoxaneactivator then this may also be the optional activator (c).

The components (a), (b), (c) and (d) may be in any molar ratio. In thecontext of an integrated process the ratio of (a) to (d) is seen asparticularly important. The ratio of (a) to (d) is preferably from10000:1 to 1:10000 and more preferably from 100:1 to 1:100. The preciseratio required depends on the relative reactivity of the components andalso on the desired properties of the product or catalyst systems.

Suitable olefinic monomers, or combinations thereof for use in thetrimerisation process of the present invention are hydrocarbon olefins,for example, ethylene, C₂₋₂₀ α-olefins, internal olefins, vinylideneolefins, cyclic olefins and dienes, propylene, 1-butene, 1-pentene,1-hexene, 4-methylpentene-1, 1-heptene, 1-octene, 1-nonene, 1-decene,1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene,styrene, 2-butene, 2-ethyl-1-hexene, cyclohexene, norbornene, butadieneand 1,5-hexadiene. Olefins with a polar functionality, such as methyl(meth)acrylate, vinyl acetate, α,ω-undecenol and the like, may also beused. The preferred monomer is ethylene. Mixtures of these monomer mayalso be used, for example a 1-butene unit and two ethylene units may beco-trimerised to form C8 olefins, or 1-hexene and ethylene co-trimerisedto C10 olefins, or 1-dodecene and ethylene co-trimerised to C16 olefins.Combinations of these co-trimerisation reactions may be performedsimultaneously, especially when one or more of the monomers are producedin-situ (e.g. a mixture of ethylene and butene can be used to formmixtures containing predominantly hexenes, octenes, and decenes.)Techniques for varying the distribution of products from these reactionsinclude controlling process conditions (e.g. concentration, reactiontemperature, pressure, residence time) and properly selecting the designof the process and are well known to those skilled in the art. Thesemonomers or combinations thereof are also suitable in the presence ofcomponent (d).

Olefinic monomers or mixtures of olefinic monomers for trimerisation maybe substantially pure or may contain olefinic impurities. One embodimentof the process of the invention comprises the trimerisation ofolefin-containing waste streams from other chemical processes or otherstages of the same process.

When operating under solution or slurry phase conditions, any diluent orsolvent that is an olefin, a mixture of olefins, or is substantiallyinert under trimerisation conditions may be employed. Mixtures of inertdiluents, with or without one or more olefins, also could be employed.The preferred diluents or solvents are aliphatic and aromatichydrocarbons and halogenated hydrocarbons such as, for example,isobutane, pentane, toluene, xylene, ethylbenzene, cumene, mesitylene,heptane, cyclohexane, methylcyclohexane, 1-hexene, 1-octene,chlorobenzene, dichlorobenzene, and the like, and mixtures such asisopar.

The trimerisation conditions can be, for example, solution phase, slurryphase, gas phase or bulk phase, with temperatures ranging from −100° C.to +300° C., preferably from 0° C. to +300° C. and more preferably from35° C. to 200° C., and at pressures of atmospheric and above, preferablyfrom atmospheric to 800 barg and more preferably from 1 barg to 100barg. If desired, the process can be operated at temperatures above 120°C., and optionally also at pressures below 30 barg. The high initialrate and low rate of deactivation of this catalyst system enables lowerpressures to be employed than would have been economically feasible withprior art catalyst systems.

Irrespective of the trimerisation technique employed, trimerisation istypically carried out under conditions that substantially excludeoxygen, water, and other materials that act as catalyst poisons. Also,trimerisation can be carried out in the presence of additives to controlselectivity, enhance activity and reduce the amount of polymer formed intrimerisation processes. Suitable additives include, but are not limitedto, hydrogen or a halide source such as GeCl₄. Exemplary halidesinclude, but are not limited to fluoride, chloride, bromide, and/oriodide.

There exist a number of options for the trimerisation reactor includingbatch, semi-batch, and continuous operation. The trimerisation andco-trimerisation reactions of the present invention can be performedunder a range of process conditions that are readily apparent to thoseskilled in the art: as a homogeneous liquid phase reaction in thepresence or absence of an inert hydrocarbon diluent such as toluene orheptanes; as a two-phase liquid/liquid reaction; as a slurry processwhere the catalyst is in a form that displays little or no solubility;as a bulk process in which essentially neat reactant and/or productolefins serve as the dominant medium; as a gas-phase process in which atleast a portion of the reactant or product olefin(s) are transported toor from a supported form of the catalyst via the gaseous state.Evaporative cooling from one or more monomers or inert volatile liquidsis but one method that can be employed to effect the removal of heatfrom the reaction. The trimerisation reactions may be performed in theknown types of gas-phase reactors, such as circulating bed, verticallyor horizontally stirred-bed, fixed-bed, or fluidised-bed reactors,liquid-phase reactors, such as plug-flow, continuously stirred tank, orloop reactors, or combinations thereof. A wide range of methods foreffecting product, reactant, and catalyst separation and/or purificationare known to those skilled in the art and may be employed: distillation,filtration, liquid-liquid separation, slurry settling, extraction, etc.One or more of these methods may be performed separately from thetrimerisation reaction or it may be advantageous to integrate at leastsome with a trimerisation reaction; a non-limiting example of this wouldbe a process employing catalytic (or reactive) distillation. Alsoadvantageous may be a process which includes more than one reactor, acatalyst kill system between reactors or after the final reactor, or anintegrated reactor/separator/purifier. While all catalyst components,reactants, inerts, and products could be employed in the presentinvention on a once-through basis, it is often economically advantageousto recycle one or more of these materials; in the case of the catalystsystem, this might require reconstituting one or more of the catalystscomponents to achieve the active catalyst system. It is within the scopeof this invention that a trimerisation product might also serve as areactant (e.g. 1-hexene, produced via the trimerization of ethylene,might be converted to decene products via a subsequent co-trimerizationreaction with ethylene.)

A number of process options can be envisaged when using the catalysts ofthe present invention in an integrated process that includes asubsequent chemical transformation, i.e. with component (d) present.These options include “in series” processes in which the trimerisationand subsequent reaction are performed in separate, linked reactors,optionally with recycling of products/reagents between the reactors, and“in situ” processes in which a both reaction steps are carried out inthe same reactor. Chemical transformations involving olefins are wellknown to those skilled in the art: non-limiting examples of the chemicalreactions that might be effected by use of a component (d) includepolymerisation and co-polymerisation, oligomerisation, hydrogenation,hydroformylation, oxidation, hydration, sulfonation, epoxidation,isomerisation, amination, cyclisation, and alkylation. A typical reactorresidence time in the polymerisation reactor is less than 4 hours,preferably less than 3 hours.

In the case of an “in series” process various purification, analysis andcontrol steps for the oligomeric product could potentially beincorporated between the trimerization and subsequent reaction stages.Recycling between reactors configured in series is also possible. Anexample of such a process would be the trimerisation of ethylene in asingle reactor with a catalyst comprising components (a), (b) andoptionally (c) followed by polymerisation of the trimerisation productwith ethylene in a separate, linked reactor to give branchedpolyethylene. Another example would be co-trimerisation of ethylene and1-butene and subsequent polymerisation of the trimerisation product togive poly(octene). Another example would be the trimerisation of anethylene-containing waste stream from a polyethylene process, followedby introduction of the product 1-hexene back into the polyethyleneprocess as a co-monomer for the production of branched polyethylene.

An example of an “in situ” process is the production of branchedpolyethylene catalysed by components (a), (b), (d) and optionally (c),added in any order such that the active catalytic species derived fromcomponents (a), (b) and optionally (c) is/are at some point present in areactor with component (d)

Both the “in series and “in situ” approaches can be adaptions of currentpolymerisation technology for the process stages including component(d). All major olefin existing polymerisation processes, includingmultiple reactor processes, are considered adaptable to this approach.One adaption is the incorporation of a trimerisation catalyst bed into arecycle loop of a gas phase polymerisation process, this could be as aside or recycle stream within the main fluidisation recycle loop and orwithin the degassing recovery and recycle system.

Polymerisation conditions when component (d) is present can be, forexample, solution phase, slurry phase, gas phase or bulk phase, withtemperatures ranging from −100° C. to +300° C., and at pressures ofatmospheric and above, particularly from 1.40 to 41 bar. Reactionconditions, will typically have a significant impact upon the properties(e.g. density, melt index, yield) of the polymer being made and it islikely that the polymer requirements will dictate many of the reactionvariables. Reaction temperature, particularly in processes where it isimportant to operate below the sintering temperature of the polymer,will typically, and preferably, be primarily selected to optimise thepolymerisation reaction conditions. The high productivity, and kineticprofile characteristics, of this new trimerisation catalyst makes the‘in-situ’ production of the comonomer, preferably hexene-1, duringpolymer, preferably polyethylene, production far more commerciallyattractive than prior art catalysts systems. This is true even at thetypical reaction temperatures and pressures for the production ofpolyethylenes with high comonomer contents such as LLDPE, VLDPE andULDPE (preferably between 50° C. and 100° C., depending upon the densityof the polymer) and even when used in slurry and gas phasepolymerisation processes (preferably total gas phase pressures between15 and 30 bar and ethylene pressures between 10 and 70 percent of thegas phase). If desired, the catalyst can be used to polymerise ethyleneunder high pressure/high temperature process conditions wherein thepolymeric material forms as a melt in supercritical ethylene. Preferablythe polymerisation is conducted under gas phase fluidized bed or stirredbed conditions. Also, polymerisation or copolymerisation can be carriedout in the presence of additives to control polymer or copolymermolecular weights. The use of hydrogen gas as a means of controlling theaverage molecular weight of the polymer or copolymer applies generallyto the polymerization process of the present invention.

Slurry phase polymerisation conditions or gas phase polymerisationconditions are particularly useful for the production of high or lowdensity grades of polyethylene, and polypropylene. In these processesthe polymerisation conditions can be batch, continuous orsemi-continuous. Furthermore, one or more reactors may be used, e.g.from two to five reactors in series. Different reaction conditions, suchas different temperatures or hydrogen concentrations may be employed inthe different reactors. In cascade operation the trimerisation catalystmay be added to any or all of the polymerisation reactors concerned. Ifadded to the first reactor and carried through to subsequent reactors,the trimerisation catalyst may, or may not, be supplemented insubsequent reactors with fresh trimerisation or polymerisation catalyst,it may be deactivated in subsequent reactors through addition ofreversible or irreversible poisons that partially or fully kill thetrimerisation catalyst or though addition of additional polymerisationcatalysts or modifiers that deactivate the trimerisation catalyst.

In the slurry phase process and the gas phase process, the catalyst isgenerally supported and metered and transfered into the polymerizationzone in the form of a particulate solid either as a dry powder (e.g.with an inert gas, ethylene or an olefin) or as a slurry. In addition,an optional activator can be fed to the polymerisation zone, for exampleas a solution, separately from or together with the solid catalyst.Components (a)-(d) can be added to any part of the polymerisationreactor either on the same support particle or as a physical mixture ondifferent support particles, or may be added separately to the same ordifferent parts of the reactor sequentially in any order orsimultaneously. Alternatively, (a)-(d) may be unsupported andindependently added to any part of the polymerisation reactorsimultaneously or sequentially together or separately. The ratio of theprimary monomer to the other (co)monomers has a significant impact onthe properties of the polymer formed (eg density) and it is usuallydesirable to be tightly controlled. This ratio may be primarilycontrolled by altering the concentration or partial pressure of eitherthe primary monomer and/or the comonomer(s). Typically the primarymonomer concentration will be controlled independently of the ratio tocomonomers (for other reasons such as activity) and the primary monomerto comonomer ratio(s) may be controlled by varying the rate ofintroduction of trimerisation catalyst or by altering reactionconditions which preferentially impact the trimerisation reaction overthe polymerisation reaction or which impacts upon the distribution ofcomonomers actually formed (eg by using reversible poisons/activators).Fresh comonomer feed may additionally be introduced to thepolymerisation reactor to control the ratio. It may be desirable topreferentially purge certain (co)monomer(s) that are formed in thetrimerisation reaction by, for example, heating or cooling a vapour (orliquid) slip (or recycle) stream within the polymerisation reaction (ordegassing) systems. This may for example be optimised by controllingcompressor knock-out or interstage conditions in recycle or degassingvent recovery compressors or by using dedicated condensing exchangers ordistillation apparatus.

The rate of addition of each component may be independently controlledto allow variations in the ratio of components and the density of thepolymer produced. Pressure, temperature, hydrogen addition, halogenatedhydrocarbon addition, electron donor addition, activator/retarderaddition and other suitable variables may also be varied to control theactivity of each component and also allow control of the polymerproduced.

Once the polymer product is discharged from the reactor, any associatedand absorbed hydrocarbons are substantially removed, or degassed, fromthe polymer by, for example, pressure let-down or gas purging usingfresh or recycled steam, nitrogen or light hydrocarbons (such asethylene). Recovered gaseous or liquid hydrocarbons may be recycled to apurification system or the polymerisation zone.

In the slurry phase polymerisation process the polymerisation diluent iscompatible with the polymer(s) and catalysts, and may be an alkane suchas hexane, heptane, isobutane, or a mixture of hydrocarbons orparaffins. The polymerization zone can be, for example, an autoclave orsimilar reaction vessel, or a continuous liquid full loop reactor, e.g.of the type well-known in the manufacture of polyethylene by thePhillips Process. When the polymerisation process of the presentinvention is carried out under slurry conditions the polymerisation ispreferably carried out at a temperature above 0° C., most preferablyabove 15° C. Under slurry conditions the polymerisation temperature ispreferably maintained below the temperature at which the polymercommences to soften or sinter in the presence of the polymerisationdiluent. If the temperature is allowed to go above the lattertemperature, fouling of the reactor can occur. Adjustment of thepolymerisation within these defined temperature ranges can provide auseful means of controlling the average molecular weight of the producedpolymer. A further useful means of controlling the molecular weight isto conduct the polymerization in the presence of hydrogen gas which actsas chain transfer agent. Generally, the higher the concentration ofhydrogen employed, the lower the average molecular weight of theproduced polymer.

In bulk polymerisation processes, liquid monomer such as propylene isused as the polymerisation medium.

Methods for operating gas phase polymerisation processes are well knownin the art. Such methods generally involve agitating (e.g. by stirring,vibrating or fluidising) a bed of catalyst, or a bed of the targetpolymer (i.e. polymer having the same or similar physical properties tothat which it is desired to make in the polymerisation process)containing a catalyst, and feeding thereto a stream of monomer (underconditions such that at least part of the monomer polymerises in contactwith the catalyst in the bed. The bed is generally cooled by theaddition of cool gas (e.g. recycled gaseous monomer) and/or volatileliquid (e.g. a volatile inert hydrocarbon, or gaseous monomer which hasbeen condensed to form a liquid). The polymer produced in, and isolatedfrom, gas phase processes forms directly a solid in the polymerisationzone and is free from, or substantially free from liquid. As is wellknown to those skilled in the art, if any liquid is allowed to enter thepolymerisation zone of a gas phase polymerisation process the quantityof liquid in the polymerisation zone is small in relation to thequantity of polymer present. This is in contrast to “solution phase”processes wherein the polymer is formed dissolved in a solvent, and“slurry phase” processes wherein the polymer forms as a suspension in aliquid diluent.

The gas phase process can be operated under batch, semi-batch, orso-called “continuous” conditions. It is preferred to operate underconditions such that monomer is continuously recycled to an agitatedpolymerisation zone containing polymerisation catalyst, make-up monomerbeing provided to replace polymerised monomer, and continuously orintermittently withdrawing produced polymer from the polymerisation zoneat a rate comparable to the rate of formation of the polymer, freshcatalyst being added to the polymerisation zone to replace the catalystwithdrawn from the polymerisation zone with the produced polymer.

Methods for operating gas phase fluidized bed processes for makingpolyethylene, ethylene copolymers and polypropylene are well known inthe art. The process can be operated, for example, in a verticalcylindrical reactor equipped with a perforated distribution plate tosupport the bed and to distribute the incoming fluidising gas streamthrough the bed. The fluidising gas circulating through the bed servesto remove the heat of polymerisation from the bed and to supply monomerfor polymerization in the bed. Thus the fluidising gas generallycomprises the monomer(s) normally together with some inert gas (e.g.nitrogen or inert hydrocarbons such as methane, ethane, propane, butane,pentane or hexane) and optionally with hydrogen as molecular weightmodifier. The hot fluidising gas emerging from the top of the bed is ledoptionally through a velocity reduction zone (this can be a cylindricalportion of the reactor having a wider diameter) and, if desired, acyclone and or filters to disentrain fine solid particles from the gasstream. The hot gas is then led to a heat exchanger to remove at leastpart of the heat of polymerisation. Catalysts are preferably fedcontinuously or at regular intervals to the bed. At start up of theprocess, the bed comprises fluidisable polymer which is preferablysimilar to the target polymer. Polymer is produced continuously withinthe bed by the polymerization of the monomer(s). Preferably means areprovided to discharge polymer from the bed continuously or at regularintervals to maintain the fluidized bed at the desired height. Theprocess is generally operated at relatively low pressure, for example,at 10 to 50 bars, and at temperatures for example, between 50 and 135°C. The temperature of the bed is maintained below the sinteringtemperature of the fluidized polymer to avoid problems of agglomeration.

In the gas phase fluidized bed process for polymerisation of olefins theheat evolved by the exothermic polymerisation reaction is normallyremoved from the polymerisation zone (i.e. the fluidised bed) by meansof the fluidising gas stream as described above. The hot reactor gasemerging from the top of the bed is led through one or more heatexchangers wherein the gas is cooled. The cooled reactor gas, togetherwith any make-up gas, is then recycled to the base of the bed. In thegas phase fluidised bed polymerisation process of the present inventionit is desirable to provide additional cooling of the bed (and therebyimprove the space time yield of the process) by feeding a volatileliquid to the bed under conditions such that the liquid evaporates inthe bed thereby absorbing additional heat of polymerisation from the bedby the “latent heat of evaporation” effect. When the hot recycle gasfrom the bed enters the beat exchanger, the volatile liquid can condenseout. In one embodiment of the present invention the volatile liquid isseparated from the recycle gas and reintroduced separately into the bed.Thus, for example, the volatile liquid can be separated and sprayed intothe bed. In another embodiment of the present invention the volatileliquid is recycled to the bed with the recycle gas. Thus the volatileliquid can be condensed from the fluidising gas stream emerging from thereactor and can be recycled to the bed with recycle gas, or can beseparated from the recycle gas and then returned to the bed.

The method of condensing liquid in the recycle gas stream and returningthe mixture of gas and entrained liquid to the bed is described inEP-A-0089691 and EP-A-0241947. It is preferred to reintroduce thecondensed liquid into the bed separate from the recycle gas using theprocess described in our U.S. Pat. No. 5,541,270.

A number of process options can be envisaged when using the catalysts ofthe present invention in an integrated process to prepare higherpolymers i.e when component (d) is present. These options include “inseries” processes in which the trimerisation and subsequentpolymerisation are carried in separate but linked reactors and “in situ”processes in which a both reaction steps are carried out in the samereactor.

In the case of a gas phase “in situ” polymerisation process, component(d) can, for example, be introduced into the polymerisation reactionzone in liquid form, for example, as a solution in a substantially inertliquid diluent. Components (a), (b), (c) and (d) may be independentlyadded to any part of the polymerisation reactor simultaneously orsequentially together or separately. Under these circumstances it ispreferred the liquid containing the component(s) is sprayed as finedroplets into the polymerisation zone. The droplet diameter ispreferably within the range 1 to 1000 microns. EP-A-0593083 discloses aprocess for introducing a polymerisation catalyst into a gas phasepolymerization. The methods disclosed in EP-A-0593083 can be suitablyemployed in the polymerisation process of the present invention ifdesired.

Although not usually required, upon completion of polymerisation orcopolymerisation, or when it is desired to terminate polymerisation orcopolymerisation or at least temporarily deactivate the catalyst orcatalyst component of this invention, the catalyst can be contacted withwater, alcohols, acetone, or other suitable catalyst deactivators amanner known to persons of skill in the art.

The trimerisation catalyst is preferably (but optionally) added beforethe polymerization catalyst such that the desired primary monomer tocomonomer(s) ratio is established prior to introduction of thepolymerization catalyst. The desired comonomer composition at start-upmay however be achieved through introduction of fresh comonomer feed orthrough judicious initiation of the trimerisation reaction before orduring polymerization catalyst introduction.

In the presence of component (d) the polymerisation process of thepresent invention provides polymers and copolymers, especially ethylenepolymers, at high productivity (based on the amount of polymer orcopolymer produced per unit weight of complex employed in the catalystsystem). This means that relatively very small quantities of transitionmetal complexes are consumed in commercial processes using the processof the present invention. It also means that when the polymerisationprocess of the present invention can be operated under polymer recoveryconditions that do not employ a catalyst separation step, thus leavingthe catalyst, or residues thereof, in the polymer (e.g. as occurs inmost commercial slurry and gas phase polymerization processes), theamount of transition metal complex in the produced polymer can be verysmall.

By varying the ratio of components (a) (b), optionally (c) and (d)and/or by adding additional comonomers, catalysts of the presentinvention can provide a wide variety of branched polymers differing indensity and in other important physical properties.

A range of polyethylene polymers are considered accessible includinghigh density polyethylene, medium density polyethylene, low densitypolyethylene, ultra low density polyethylene and elastomeric materials.Particularly important are the polymers having a density in the range of0.91 to 0.93, generally referred to in the art as linear low densitypolyethylene. Such polymers and copolymers are used extensively in themanufacture of flexible blown or cast film.

Poly(1-hexene), poly(1-octene) and the like are also consideredaccessible, as are copolymers of e.g. 1-hexene and propylene, 1-hexeneand 1-octene and terpolymers of e.g. ethylene, 1-hexene and vinylacetate.

Dienes could also be incorporated into the polymeric products to enablecross-linking for e.g. elastomer and wire and cable applications

Depending upon the use of the polymer product, minor amounts ofadditives are typically incorporated into the polymer formulation suchas acid scavengers, antioxidants, stabilizers, and the like. Generally,these additives are incorporated at levels of about 25 to 2000 ppm,typically from about 50 to about 1000 ppm, and more typically 400 to1000 ppm, based on the polymer.

In use, polymers or copolymers made according to the invention in theform of a powder are conventionally compounded into pellets. Examples ofuses for polymer compositions made according to the invention includeuse to form fibres, extruded films, tapes, spunbonded webs, moulded orthermoformed products, and the like. The polymers may be blown or castinto films, or may be used for making a variety of moulded or extrudedarticles such as pipes, and containers such as bottles or drums.Specific additive packages for each application may be selected as knownin the art. Examples of supplemental additives include slip agents,anti-blocks, anti-stats, mould release agents, primary and secondaryanti-oxidants, clarifiers, nucleants, uv stabilizers, and the like.Classes of additives are well known in the art and include phosphiteantioxidants, hydroxylamine (such as N,N-dialkyl hydroxylamine) andamine oxide (such as dialkyl methyl amine oxide) antioxidants, hinderedamine light (uv) stabilizers, phenolic stabilizers, benzofuranonestabilizers, and the like. Various olefin polymer additives aredescribed in U.S. Pat. Nos. 4,318,845, 4,325,863, 4,590,231, 4,668,721,4,876,300, 5,175,312, 5,276,076, 5,326,802, 5,344,860, 5,596,033, and5,625,090.

Fillers such as silica, glass fibers, talc, and the like, nucleatingagents, and colourants also may be added to the polymer compositions asknown by the art.

The present invention is illustrated in the following Examples.

EXAMPLES

All manipulations were performed under anaerobic conditions. Solventsand gases were dried and degassed by standard procedures. Chemicals werepurchased from the Aldrich Chemical Company unless stated otherwise.Methyl alumoxane (MAO) and modified methyl alumoxane (MMAO) werepurchased from Witco as 10% w/w solutions in toluene or heptanesrespectively. (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ wassynthesized by literature procedures (See example 12 of WO97/37765).Cr(p-tolyl)Cl₂(THF)₃ was synthesized by literature procedure (Daly, J.J.; Seeden, R. P. A.; J.Chem.Soc.A, 1967, 736). Reaction products wereanalysed by GCMS using 50 m×0.3 mm id, CP sil. CBS-MS, df=0.4 μmcolumns, an initial temperature of −30° C., hold 1 min, ramp rate 7°C./min, final temperature 280° C. and final hold of 5 mins. Molarquantities of catalyst are based upon the molar quantity of chromiumsource used in their preparation.

Example 1

A Schlenk tube was charged with CrCl₃(THF)₃ (8 mg, 0.02 mmol) and(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 10 mlTHF was added and the solution stirred for 2 hours. After this time,solvent was removed under reduced pressure and the resultant solidsuspended in 50 ml toluene. MAO (4.2 ml, 6.0 mmol, 300 equivalents) wasadded and an immediately a green solution was observed. The solutionplaced under an ethylene atmosphere (1 bar). An immediate exotherm wasobserved. The reaction was run for 60 minutes during which time thevessel was left open to a supply of ethylene at 1 bar. The catalyst wasthen destroyed by addition of 50 ml dilute aqueous HCl, the organiclayer separated and dried over MgSO₄. The product mass, recorded byweighing the mass gain of the Schlenk reaction vessel, was 10.3 g.

GCMS analysis of the reaction products gave the following productdistribution: wt % Total Product Butenes 0.04 1-Hexene 82.17 2-Hexene0.44 3-Hexene 0.15 1-Octene 1.37 Decenes 14.39 C12 olefins 0.20 C14olefins 0.78 C16 olefins 0.00 C18 olefins 0.00

Example 2

The procedure of Example 1 was followed, with the exception that 300equivalents of MMAO (4.2 ml, 6.0 mmol) was used in place of MAO. Theproduct mass was 8.8 g.

Example 3

The procedure of Example 1 was followed, with the exception that 100equivalents of (iBu₂AlO)₂ (2.0M solution in toluene, 1.0 ml, 2.0 mmol)was used in place of MAO. The product mass was 1.3 g.

Example 4

The procedure as Example 1 was followed with the exception that CrCl₂ (3mg, 0.02 mmol) was used in place of CrCl₃(THF)₃. The product mass was5.6 g.

Example5

A Schlenk vessel was charged with Cr(p-tolyl)Cl₂(THF)₃ (9 mg, 0.02 mmol)and (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 50ml toluene was added, and the solution stirred for 5 minutes. MMAO (4.2ml, 6.0 mmol) 300 equivalents) was added and the solution placed underan ethylene atmosphere (1 bar). The reaction was run for 60 minutesduring which time the vessel was left open to a supply of ethylene at 1bar. The reaction was worked-up as described in example 1. The productmass was 11.0 g.

Example 6

The procedure as Example 1 was followed with the exception that 0.04mmol (20 mg) of (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ was usedrather than 0.02 mmol. The product mass was 9.5 g.

Example 7

The procedure as Example 2 was followed with the exception that 0.01mmol (5 mg) of (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ was usedrather than 0.02 mmol. The product mass was 3.3 g.

Example 8

A Schlenk tube was charged with(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (415 mg, 0.8 mmol) andCrCl₃(THF)₃ (300 mg, 0.8 mmol) and 30 ml dichloromethane added. A brightblue solution formed almost immediately which was stirred for 2 hours.After this time solvent was removed under reduced pressure to yield ablue solid; this was washed with diethyl ether and dried in vacuo. Afurther Schlenk tube was charged with mg of this compound and 50 mltoluene added. MMAO (16.8 ml, 24 mmol, 300 equivalents) was added andthe solution placed under an ethylene atmosphere (1 bar). The reactionwas run for 60 minutes during which time the vessel was left open to asupply of ethylene at 1 bar. The reaction was worked-up as described inexample 1. The product mass was 2.5 g.

Example 9 Preparation of MAO on Silica

Toluene (200 ml) was added to a vessel containing silica (preparedaccording to procedures described in WO 99/12981 example 37.1. Silicawas supplied by Crosfield as grade ES70X), calcined at 200° C.overnight, 20.5 g after calcination) under an inert atmosphere. Theslurry was mechanically stirred and MAO (1.5 M, 62.1 mmol, 41.4 ml) wasadded via syringe. The mixture was stirred for 1 hour at 80° C. beforeremoving excess toluene and drying under vacuum to obtain 15% w/w MAO onsilica in quantitative yield.

Trimerisation Using a Supported Catalyst Composition

A Schlenk vessel was charged with CrCl₃(THF)₃ (8 mg, 0.02 mmol) and(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 10 mlTHF was added and the solution stirred for 2 hours. After this time,solvent was removed under reduced pressure and the resultant solidsuspended in 20 ml toluene. MAO (1.4 ml, 2 mmol, 100 equivalents) wasadded and an immediately a green solution was observed. This solutionwas then transferred via cannula to a Schlenk tube containing a slurryof 15% w/w MAO on silica (prepared as described above) in toluene (1 gof MAO/Silica in 30 ml toluene). The green colour of the solution wasquickly transferred onto the silica/MAO and a colourless supernatantremained. This slurry was stirred and placed under an ethyleneatmosphere (1 bar). The reaction was run for 60 minutes during whichtime the vessel was left open to a supply of ethylene at 1 bar. Thereaction was worked-up as described in example 1. The product mass was8.9 g. wt % Total Product 1-Hexene 62 Octenes 0.28 Decenes 30.3

Example 10

A Schlenk vessel was charged with CrCl₃(THF)₃ (8 mg, 0.02 mmol) and(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 10 mlTHF was added and the solution stirred for 2 hours. After this time,solvent was removed under reduced pressure, the resultant solidsuspended in 10 ml toluene and MAO (4.2 ml, 6.0 mmol, 300 equivalents)added. This solution was then injected into an autoclave at 8 barethylene pressure and 50° C. The diluent was isobutane. The reaction wasrun for 1 hour at 8 bar ethylene pressure and 50° C. after which timeethylene and isobutane gases were vented. The reaction products werethen worked up as described in Example 1. The mass of product recoveredwas 40.0 g and the productivity over one hour was 2000 g/mmol.h. GCMSanalysis gave the following product distribution: wt % Total ProductButenes 0.00 1-Hexene 88.37 2-Hexene 0.12 3-Hexene 0.00 Octenes 3.95Decenes 6.61 C12 olefins 0.33 C14 olefins 0.20 C16 olefins 0.00 C18olefins 0.00

Example 11

The procedure of Example 10 was followed with the following exceptions:500 ml toluene diluent was used in place of isobutene and 0.01 mmol ofcatalyst was used. The reactor conditions were maintained at 50° C. and8 bar ethylene pressure over the 60 minute run time. A stable gas uptakeprofile over the run time was observed. The mass of product recoveredwas 72.7 g and the productivity over one hour was 7270 g/mmol.h (134 700g/gCr.h.) wt % Total Product 1-Hexene 86 Octenes 1.8 Decenes 8.7

Example 12

The procedure of Example 11 was followed with the exceptions that thereactor conditions were maintained at 80° C. and 20 bar ethylenepressure over the 60 minute run time. 0.0025 mmol of catalyst was used.The mass of product recovered was 141 g and the productivity over onehour was 56400 g/mmol.h (1 033 200 g/gCr.h.) wt % Total Product 1-Hexene88.8 Octenes 1.8 Decenes 7.4

Example 13

The procedure of Example 11 was followed with the exceptions that thereactor conditions were maintained at 108° C. and 8 bar ethylenepressure over the 60 minute run time. 0.01 mmol of catalyst was used.The mass of product recovered was 51.6 g and the productivity over onehour was 5160 g/mmol.h (95 900 g/gCr.h) wt % Total Product 1-Hexene 86.6Decenes 11

Example 14

The procedure of Example 11 was followed with the exceptions that 1 barof hydrogen was added to the reactor before the run. 0.01 mmol ofcatalyst was used. The mass of product recovered was 94.7 g and theproductivity over one hour was 9470 g/mmol.h (175 300 g/gCr.h.) wt %Total Product 1-Hexene 82 Octenes 0.45 Decenes 13.2

Example 15

The procedure of Example 11 was followed with the exception that 0.01mmol of a supported catalyst, prepared as described in Example 8, wasused. The mass of product recovered was 49.8 g and the productivity overone hour was 4980 g/mmol.h (90 406 g/gCr.h.) wt % Total Product 1-Hexene89 Octenes 0.58 Decenes 7.9

Example 16

The procedure of Example 11 was followed with the exceptions that 100 mlof 1-butene was added to the reactor before the run and 400 ml oftoluene diluent was used. The reactor conditions were maintained at 80°C. and 4 bar ethylene pressure. 0.02 mmol of catalyst was used. The massof product recovered was 49.4 g and the productivity over one hour was2470 g/mmol.h (46125 g/gCr.h.) wt % Total Product 1-Hexene 60 Octenes 25Decenes 10.9

Example 17

The procedure of Example 1 was followed with the exceptions that the runtime in this case was 90 minutes and the product mass was recorded byweighing the mass gain of the Schlenk reaction vessel at various timesthrough the run. Time (mins) 15 30 45 60 90 Mass gain (g) 2.7 5.2 7.610.0 13.0

GCMS analysis of the product after 90 minutes gave the following productdistribution: wt % Total Product Butenes 0.00 1-Hexene 64.10 2-Hexene0.13 3-Hexene 0.00 Octenes 0.44 Decenes 28.93 C12 olefins 0.13 C14olefins 4.99 C16 olefins 0.00 C18 olefins 0.59

Example 18

The procedure of Example 2 was followed with the exceptions that 20 mlof toluene was used and 20 ml of 1-dodecene was added at the start ofthe run. The product mass was 2.1 g. wt % Total Product 1-Hexene 37Decene 27 C16 olefins 29

Example 19

The procedure of Example 2 was followed with the exceptions that 20 mlof toluene was used and 20 ml of 1-tetradecene was added at the start ofthe run. The product mass was 3.2 g. wt % Total Product 1-Hexene 35.3Decene 6.7 C18 olefins 50.8

Example 20

The procedure of Example 9 was followed with the exceptions that 20 mlof toluene was used and 20 ml of 1-dodecene was added at the start ofthe run, in this case the run was for 4.5 hours. The product mass was7.5 g. wt % Total Product 1-Hexene 38 Decene 24 C16 olefins 38

Example A (Comparative)

The procedure of Example 1 was followed with the exceptions that1,2-bis(diphenylphosphino)ethane (8 mg, 0.02 mmol) was used in place of(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂. No product was formed.

Example 21

The procedure of Example 1 was followed, with the exception thattris(2-methoxymethoxyphenyl)phosphane (18 mg, 0.04 mmol) was used inplace of (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂. The product masswas 1.2 g.

GCMS analysis of the reaction products gave the following productdistribution: wt % Total Product 1-Hexene 90.66 2-Hexene 2.94 1-Octene2.85 Decenes 3.54

Example B (Comparative)

The procedure of Example 20 was followed with the exception thattriphenylphosphane (11 mg, 0.04 mmol) was used in place oftris(2-methoxymethoxyphenyl)phosphane. No product was formed

Example 22 (Co)Polymerisation of Ethylene

An autoclave was charged with isobutane (500 ml) and triethylaluminium(2.0M solution in toluene, 1.5 ml, 3 mmol). The autoclave waspressurized to 8 bar ethylene pressure and heated to 50° C.

A catalyst (0.02 mmol), prepared as described in Example 8, was theninjected as a slurry in 10 ml toluene. Almost immediately, a slurry ofZiegler catalyst (0.05 g), prepared according to U.S. Pat. No.5,470,812, example A, was injected as a slurry in 10 ml toluene. Thereaction was run for 1 hour at 8 bar ethylene pressure and 50° C. afterwhich time ethylene and isobutane gases were vented. The resultantpolymer was washed with dilute aqueous HCl and then methanol and driedin vacuo. The mass of polymer recovered was 36.0 g. NMR spectroscopy ofthe polymer shows the presence of butyl branches, indicating that anethylene/1-hexene copolymer was produced.

Example 23 (Co)Polymerisation of Ethylene

A supported catalyst (0.01 mmol) was prepared as described in Example 9in 40 ml toluene. In a separate Schlenk tube, [rac-(ethylene bridged bisindenyl) zirconium dichloride] (mg, 0.01 mmol) was disolved in 10 mltoluene and MMAO (7 ml, 10.0 mmol, 1000 equivalents) added. This secondsolution was added via canula to the supported catalyst slurry and theresultant slurry stirred under an ethylene atmosphere at 1 bar. Thereaction was run for 60 minutes during which time the vessel was leftopen to a supply of ethylene at 1 bar. The catalysts were then destroyedby careful addition of 50 ml dilute aqueous HCl. Both organic andaqueous fractions were then added to 500 ml of acetone, causingprecipitation of the polymer produced. The polymer was washed withfurther portions of acetone and dried in vacuo. The mass of polymerrecovered was 3.4 g. NMR spectroscopy of the polymer shows the presenceof butyl branches, indicating that an ethylene/1-hexene copolymer wasproduced.

1-45. (Cancelled)
 46. A process for the trimerization of olefins,comprising contacting a monomeric olefin or mixture of olefins undertrimerization reaction conditions in a trimerization reactor with acatalyst which comprises: (a) a source of a Group 3 to 10 transitionmetal: (b) a ligand containing at least one phosphorus, arsenic orantimony atom bound to at least one hydrocarbyl or heterohydrocarbylgroup having a polar substituent, but excluding the case where all suchpolar substituents are phosphane, arsane or stibane groups; andoptionally (c) an activator.
 47. The process according to claim 46,wherein the catalyst is supported.
 48. The process according to claim47, wherein the support is selected from silica, alumina, MgCl₂,zirconia, polyethylene, polypropylene, polystyrene, orpoly(aminostyrene).
 49. The process according to claim 46, whereincomponent (a) is a source of chromium, molybdenum or tungsten.
 50. Theprocess according to claim 46, wherein the ligand of component (b) hasthe formula(R¹)(R²)X—Y—X(R³)(R⁴) orX(R¹)(R²)(R³), wherein X is phosphorus, arsenic or antimony; Y is alinking group; and R¹, R², R³ and R⁴ are each independently hydrocarbyl,substituted hydrocarbyl, heterohydrocarbyl or substitutedheterohydrocarbyl groups, at least one of which in each formula has apolar substituent which is not a phosphane, arsane or stibane group, andany of the groups R¹-R⁴ may independently be linked to one or more ofeach other or to the bridging group Y, to form a cyclic structuretogether with X or X and Y.
 51. The process according to claim 50,wherein X is phosphorus.
 52. The process according to claim 50, whereinthe polar substituents are independently selected from the groupconsisting of methoxy, ethoxy, isopropoxy, C₃-C₂₀ alkoxy, phenoxy,pentafluorophenoxy, trimethylsiloxy, dimethylamino, methylsulphanyl,tosyl, methoxymethyl, methylthiomethyl, 1,3-oxazolyl, methoxymethoxy,hydroxyl, amino, sulphate, nitro, phosphane, arsane and stibane.
 53. Theprocess according to claim 50, wherein those of R¹ to R⁴ having polarsubstituents are each independently o-methoxy phenyl or o-methoxymethoxyphenyl.
 54. The process according to claim 46, wherein component (b) isselected from the group consisting of the following:(2-methoxyphenyl)(phenyl)PN(Me)P(phenyl)₂,(2-methoxyphenyl)₂PN(Me)P(phenyl)₂,(2-methoxyphenyl)(phenyl)PN(Me)P(2-methoxyphenyl)(phenyl),(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂,(2-ethoxyphenyl)₂PN(Me)P(2-ethoxyphenyl)₂,(2-isopropoxphenyl)₂PN(Me)P(2-isopropoxyphenyl)₂,(2-hydroxyphenyl)₂PN(Me)P(2-hydroxyphenyl)₂,(2-nitrophenyl)₂PN(Me)P(2-nitrophenyl)₂,(2,3-dimethoxyphenyl)₂PN(Me)P(2,3-dimethoxyphenyl)₂,(2,4-dimethoxyphenyl)₂PN(Me)P(2,4-dimethoxyphenyl)₂,(2,6-dimethoxyphenyl)₂PN(Me)P(2,6-dimethoxyphenyl)₂,(2,4,6-trimethoxyphenyl)₂PN(Me)P(2,4,6-trimethoxyphenyl)₂,(2-dimethoxyphenyl)(2-methylphenyl)PN(Me)P(2-methylphenyl)₂,[2-(dimethylamino)phenyl]₂PN(Me)P[2-(dimethylamino)phenyl]₂,(2-methoxymethoxyphenyl)₂PN(Me)P(2-methoxymethoxyphenyl)₂,(2-methoxyphenyl)₂PN(Ethyl)P(2-methoxyphenyl)₂,(2-methoxyphenyl)₂PN(Phenyl)P(2-methoxyphenyl)₂,(2-methoxyphenyl)₂PN(Me)N(Me)P(2-methoxyphenyl)₂,(2-methoxyphenyl)₂PCH₂P(2-methoxyphenyl)₂(2-methoxyphenyl)₂PCH₂CH₂P(2-methoxyphenyl)₂,tri(2-methoxymethoxyphenyl)phosphane i.e.,

 and tri(2-methoxyphenyl)phosphane.
 55. The process according to claim46, wherein component (c) is selected from the group consisting oftrimethylaluminium (TMA), triethylaluminium (TEA), tri-isobutylaluminium(TIBA), tri-n-octylaluminium, methylaluminium dichloride, ethylaluminiumdichloride, dimethylaluminium chloride, diethylaluminium chloride,ethylaluminiumsesquichloride, methylaluminiumsesquichloride, alumoxanes,tetrafluoroboric acid etherate, silver tetrafluoroborate, sodiumhexafluoroantimonate, boroxines, NaBH₄, trimethylboron, triethylboron,dimethylphenylammoniumtetra(phenyl)borate, trityltetra(phenyl)borate,triphenylboron, dimethylphenylammonium tetra(pentrafluorophenyl)borate,sodium tetrakis[(bis-3,5-trifluoromethyl)phenyl]borate,H⁺(OEt₂)₂[(bis-3,5-trifluoromethyl)phenyl]borate,trityltetra(pentrafluorophenyl)borate and tris(pentafluorophenyl) boron,and mixtures thereof.
 56. The process according to claim 46, wherein theolefin or mixture of olefins is additionally contacted with a furthercatalyst (d) suitable for the polymerization, oligomerization or otherchemical transformation of olefins, such that the trimerization productsare incorporated into a higher polymer or other chemical product. 57.The process according to claim 46, wherein the monomeric olefin isethylene.
 58. The process of claim 46, wherein the mixture of olefinscomprises ethylene and one or more C₃-C₃₆ monoolefin.
 59. The processaccording to claim 58, wherein the C₃-C₃₆ monoolefin is a C₄-C₂₀monoolefin.
 60. The process according to claim 59, wherein the C₄-C₂₀monoolefin comprises butene, hexene, decene, a C₁₂ olefin or a C₁₄olefin.
 61. The process according to claim 46, wherein at least 85 wt %of the trimerization reaction product is one of the following: 1-hexene,1-octene, 1-decene, a C₁₂ olefin, a C₁₄ olefin, a C₁₆ olefin, or a C₁₈olefin.
 62. The process according to claim 46, wherein the reactiontemperature is less than 100° C., and/or the reaction pressure is below30 bara.
 63. The process according to claim 46, wherein the residencetime in the trimerization reactor is less than 4 hours.
 64. The processaccording to claim 46, wherein the trimerization reaction conditions aresolution phase, slurry phase or gas phase.
 65. The process according toclaim 64, wherein the reaction is conducted under gas phase fluidizedbed conditions.
 66. The process according to claim 56, wherein thetrimerization reactor is upstream or downstream of at least onepolymerization or oligomerization reactor.
 67. The process according toclaim 56, wherein the trimerization reactor is incorporated into thereaction loop of at least one polymerization or oligomerization reactor.68. The process according to claim 67, wherein the trimerization reactoris incorporated into a side-stream taken from said reaction loop. 69.The process according to claim 56, wherein the trimerization reactionproduct is produced in or introduced into at least one polymerization oroligomerization reactor.
 70. The process according to claim 56, whereinat least one trimerization reaction product is separated from theremainder of the trimerization reaction products prior to(re)introduction into the polymerization or oligomerization reactor. 71.The process according to claim 46, wherein the trimerization reaction isconducted in the presence of hydrogen and/or a halide source.